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Unit 6 Earthquakes and Volcanoes


1. What are earthquakes? Earthquakes are movement of earth s crust caused by plates shifting and releasing stored energy Rocks on either side of a fault snag and ... – PowerPoint PPT presentation

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Title: Unit 6 Earthquakes and Volcanoes

1. What are earthquakes? Earthquakes are movement of earths crust caused by plates shifting and releasing stored energy Rocks on either side of a fault snag and build up pressure When the rocks break ... shake, rattle and roll!

2. What are seismic waves? 2. Seismic waves are shock waves in the earth caused by an earthquake.

3. What are P waves? 3. P waves are primary waves. They are fast and longitudinal ( push and pull forces) P waves are the to 'arrive' at a seismic station. The P wave can move through solid rock and fluids, like water or the liquid layers of the earth. It pushes and pulls the rock it moves through just like sound waves push and pull the air.

4. What are S waves? 4. S waves are secondary or shear waves. They are slower. S waves are transverse- move from side to side. S waves move rock particles up and down, or side-to-side perpendicular to the Direction of the wave.

5. What are L waves? 5. L waves are love waves Named after a British scientist who calculated a mathematical model for a wave. L Waves are the fastest waves and move from ground to side to side. In other words, they are P or S waves that hit the surface.

6. What is the focus of an earthquake? 6. The focus is where rocks first break and move.
7. What is the epicenter? 7. The Epicenter is the point on earths surface directly above the focus.
8. What is a seismograph? 8. A seismograph is an instrument used to record seismic waves.

Earthquake Scales
9. What is the Richter Scale? 9. A Richter Scale measures the total energy released by an earthquake b) 1 means x32

Earthquake Scales
10. What is the Mercalli Intensity Scale? 10. The Mercalli Intensity Scale is a scale that measures the intensity of an earthquake. The scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures on a scale of I through XII, with I denoting a weak earthquake and XII one that causes almost complete destruction.

Earthquake Zones
11. Where are the 3 major earthquake zones? 11. Ring of Fire- is located around the edge of the Pacific Ocean. Mid-Atlantic Ridge- this zone is caused by sea floor spreading The Mediterranean Asiatic Belt- occurs because continental plates are colliding.

Earthquake Evidence
12. Describe ground level earthquake evidence 12. Ground level earthquake evidence is side to side or up and down shifts of the ground. The earth has moved mostly slow and steady and is called creep

Earthquake Evidence
13. Describe landscape evidence of earthquakes. 13. There are 5 descriptions Slide rapid down slope movement of soil, debris, rock Scarp cliff made by uplifted or subsided earth

Earthquake Evidence
13. 13. Fissures long cracks in soil or rock Tsunami an ocean wave caused by earthquakes a) can be 30m high at the shore Buildings on loose soil have more damage.

14. What is a volcano? 14. A volcano is any opening in the earths crust that release molten rock.

15. What is a vent? 15. An opening through which material reaches the surface
16. What is a crater? 16. A crater is a hollowed out area in the top of a volcano
17. What is the pipe? 17. The pipe is a long crack through which magma moves
18. What is the magma chamber? 18. A chamber with a pocket of magma.
19. What is an active volcano? 19. An active volcano has erupted during the last century.
20. What is a dormant volcano? 20. A dormant volcano has not erupted for hundreds of years, but it believed that it has the ability to erupt.
21. What is an extinct volcano? 21. A volcano is considered extinct if it has not erupted for thousands of years. http//hvo.wr.usgs.gov/volcanoes/maunakea/

22.List the sequence of events when a volcano erupts? 22. Lava flows out usually gently and quietly 2) Then an explosion of debris occurs. The following are products of a volcano pyroclasts fragments of broken rock from a volcano ash hot fine-grained material bombs large molten or semimolten chunks

23. What are cinder cone volcanoes? 23. A cinder cone formed from ash and cinders in explosive eruptions. Cinder cones volcanoes are smaller, coned shaped, and steep slopes. Example
Paricutín, Mexico
24. What are shield volcanoes? 24. Shield volcanoes are from from lava flow eruptions. They have broad with gentle slopes. An example is Muana Loa, Hawaii

25. What are composite volcanoes? 25. Composite volcanoes are formed from alternating layers of lava and pyroclasts. Characteristics include They are explosive and have lava eruptions They are large with steep slopes Examples Mt. Fuji, Japan Mt. St. Helens, Washington

26. Case study Pompeii 26. 79 CE Site was not discovered until 1748 Provided archeologists extraordinary details about daily life in Roman Empire Some believe that volcano took 2 months to completely bury the town as people were found wearing winter clothing in the summer, dates of minted coins and letters Populist tourist site in S. Italy


27. Case study Mt. St. Helen 27. Erupted 05/18/1980. Caused by an earthquake on 03/20/1980. Most deadliest and costly volcano in US history. Glacier mountain Due to the eruption, at the top of the mountain is a 1 mile long horseshoe crater. Volcano steamed until January 2008
Igneous Rock Features
28. What are batholiths? 28. Large intrusive igneous rock body that forms when magma being forced upward toward Earths crust cools slowly and solidifies underground.

29. What is a dike? 29.Magma that is forced into a crack that cuts across layers and hardens.
30. What is a volcanic neck? 30. Solid igneous core of a volcano left behind after the softer cone has been eroded.
Igneous Rock Features
31. What is a caldera? 31. Large, circular-shaped opening formed when the top of a volcano collapses. Crater Lake is an example
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